I thought I'd only use a airlock on my 6-gal carboy, but last night I saw the fermentation reaching the top of the carboy after about 24 hrs of fermentation. I switched to a blow off, and when i checked back today (after 48 hours) there was tons of stuff in the blow off tube.
Anyway, I've had blow offs like this with wheat beers, but this is the first I've had for non-wheat (about 6 batches). Just thought I'd post this in case anyone searches on 1318 London Ale III in the future.
I'll probably just always do blow off from now on.